New study analyzes pre- and post-booster seat law crash data in five states

A new analysis by the Insurance Institute for Highway Safety (IIHS) associates expanded CR laws with a 5 percent injury rate reduction and a 17 percent fatal and incapacitating injury rate reduction. Children covered by the enhanced laws were nearly three times more likely to be in CRs (including boosters) and 6 percent more likely to ride in a rear seating position.
Data from five states—Missouri, North Carolina, Pennsylvania, Wisconsin, and Wyoming—were analyzed for two years before and two years after CR law changes were fully implemented. IIHS researchers looked at the use of CRs, seating position, and per capita injury rates among child passengers affected by law enhancements. The same information set for 9- to 12-year-old children was used for comparison.
“With this study we wanted to see if extending booster requirements to older kids would make a difference in terms of restraint use and rates of injuries in crashes,” said Anne McCartt, senior vice president for research. “What we found was that five states with stricter laws are seeing measurable benefits.”
Injury, restraint use, and seating position data for children in motor vehicle crashes were extracted from the State Data System (SDS), a collection of state crash files coded from police crash reports. Injury rates were based on population estimates by single years of age for each study state.
One study limitation is the reliance on the ability of police officers to recognize and assess injury severity, restraint use, and seating position accurately and consistently. In addition, restraint usage rates and selection changes were based only on children involved in police-reported crashes.
All 50 states and the District of Columbia have laws that require children to be restrained in CRs, including boosters, but only 55 percent of 4- to 7-year-olds ride in CRs, according to The 2009 National Survey of the Use of Booster Seats(NHTSA; 2010). The same NHTSA study shows that only 39 percent of 6- to 7-year-olds ride in CRs. While previous studies provide some evidence that expanded laws are associated with injury reduction, they have primarily focused on laws that cover younger booster-aged children.
Based on the results of this more- extensive analysis, IIHS researchers concluded that stronger laws are effective at increasing the use of CRs, increasing the use of rear seats even when the laws don’t require it, reducing all severities of injuries, and especially reducing serious or fatal injuries among children covered by the expanded laws. They recommend that states consider revising laws to ensure that older children receive the best crash protection.